Smoke detector



FIG. 1 is a side elevational view of a smoke detector showing my new design;

FIG. 2 is a top plan view thereof;

FIG. 3 is a side elevational view thereof, seen in the direction of line 3--3 of FIG. 1;

FIG. 4 is a bottom plan view thereof. 

The ornamental design for a smoke detector, as shown. 